Apparatus, including an air trap for unloading liquid from tank cars



May 16, 1950 A. I HlcKl-:RSON 2,507,595

APPARATUS, INCLUDING AN AIR TRAP PoR UNLUADING LIQUID PROM TANK-CARS Filed June 26, 1944 mag xz INVENTOR A. L. HICKERSON BY/zaw ATTORNE Patented May 16, 1950 APPARATUS, INCLUDING AN AIB TRAP FOR UNLOADING LIQUID FROM TANK CARS Albert L. Hickerson, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application June 26, 1944, Serial No. 542,199

z claims. (c1. 222-372) This invention relates to methods o! and means for pumping iiuids and it has particular relation to the pumping of an inammable liquid. such as gasoline, in the rapid unloading of large containers, such as railroad tank cars.

In the art of unloading railroad tank cars it has been found inefficient with respect to time to allow the gasoline to merely drain out of the car. It has been found desirable to operate the pump So as to create suction which will quickly pull the gasoline out of the tank car with the aid of atmospheric pressure. Unfortunately, in some instances the pump has been so large and perated at such a high speed that when one or more of the tank cars was emptied the pump has drawn air into itself with the result that the electric motor driving the pump has increased its speed and electric current in the motor windings to such an extent as to catch fire. In some instances the gassing up of the unloading pump has resulted in burning up the motor and pump and even setting the entire loading rack and substantially empty tank cars on fire. When a tank car has just been emptied there is a likelihood that the incoming air will form an explosive mixture inside the tank car; and if this explosive mixture is ignited the result is to make the tank car into a bomb which will wreck the entire neighborhood.

It is necessary, especially in wartime, to 0btain the advantages of faster unloading with less labor involved and with the desirable safety feature of preventing the gassing of the unloading pump and any possible re in the unloading rack installation, and the principal object of my invention is to achieve these advantages so necessary in the rapid handling of aviation gasoline for the armed forces.

Another object of my invention is to provide a suitable method and means for pumping liquids.

Another objectv is to provide a loading rack for unloading railroad tank cars by rapid pumping in which it is impossible for the pump to become filled with gas so that the pump and pump motor will not run wild and the danger of nre is thereby reduced.

A further object is to provide a recycling bypass from a liquid pump in combination with an air trap so that the pump will pump a liquid at all times.

A further object is to simplify and speed up the unloading of liquids from tank cars by preventing gassing up of the unloading pump.

A still further object is to provide in such a recycling bypass a valve controlled by a oat in pass will be open to recycle liquid so that the Ill 2 the air trap so that when the liquid level in the air trap falls dangerously low the recycling byliquid pump will always be full of liquid.

Other objects are to provide methods and apparatus economical of material and labor and suitable for commercial competition with existing devices and in which a high safety factor is maintained with respect to possible re.

Numerous other objects and advantages will be apparent to those skilled in the art upon reading the accompanying specification and claims and studying the accompanying drawing.

In the drawings:

The single figure of the drawings is an elevational view with a portion of the ground in cross section, showing an unloading rack for railroad tank cars embodying the present invention.

In the drawing a tank car I isl one of a series of tank cars placed on railroad siding 2 for the purpose of being unloaded in a rapid manner by an unloading rack generally designated as 3.

Each tank car I is normally provided with an upper valve 4 communicating with the atmosphere and with the interior of the tank and with a belly valve 5 for controlling ow of liquid from the vbottom of the tank. This invention may obviously be applied to other valve arrangements and other types of tank cars without invention.

Unloading rack 3 may be comprised of a header 6 runningparallel to the railroad siding 2. 'Ihe header 6 may have a number of feed lines l connected thereto and spaced approximately the length of a tank car apart. A control valve 8 is provided in each feed line 1. The invention is of course also useful for only one car I and one feed line l, so the number of feed lines is not critical at all.

Feed line l is provided with a flexible connection 9, which allows some iiexibility in connecting the line l to the belly valve 5, which connection is made by any suitable means. Each feed line 1 is connected normally to the respective tank car I which is placed opposite it. Feed line 1 may be a flexible synthetic rubber hose, or may be metal with a telescopic section therein (not shown) to allow for differences in tank car construction and some range as to how they are spotted on the siding by the train crew. Such feed lines are old and any of these old feed lines may be used.

The unloading rack 3 has a main line II leading from header 6 to an air trap I2. Air trap I2 has a drain valve I3 which generally remains closed. Air trap I2 has an inverted U tube I4 whiehrisesabovethehighestpossiblelevelo! liqmdinanyofthetankcarsiandthenleads to a control valve Il located at a convenient height for operation by the man on the Job. valve Il opensorclosesthetopoitheairtrap the atmosphere. From the lower portion of trap I2aline llrunstoaliquidpump I1. typeofpumpmaybeemployedandpump I1 is driven by any type of motor (not shown). Valvenil controls the iiow of liquid through nine Pump I1 discharges through discharge line Il, and discharge line I may lead to suitable tanks or other tank vehicles, such as automobile tank trucks (not shown). Discharge line I5 has a control valve 2| therein and a check valve 22 permitting flow of iiuids therethrough to the right of the drawing but preventing ilow in the reverse direction.

Between pump I1 and check valve 22 line I5 is provided with a recycling bypass 22. I'he recycling bypass may be provided with valves 24 and 25 for manually shutting oII ilow therethrough, but like valve I5, neither of the valves 25 or 25 is essential to the operation of the invention but each is convenient at times in the re-v moval of parts, repair, or replacement.

Recycling bypass 25 is provided with a control valve 25- which closes bypass 22 whenever the liquid level in air trap I2 is above level 21. The operation of the valve 25 to accomplish this purpose is made possible by float chamber 25 and pipes 25 and 2| connecting the iloat chamber with the interior of air trap I2 above and below level 21. The usual float (not shown) is provided in chamber 25, and this iloat operates valve 25 as set forth by any suitable linkage old in the art.

The liquid is at level 22 at the particular moment of unloading depicted in the drawing.

Operation The tank cars I to be unloaded are spotted on the siding 2 so that their belly valves 5 are opposite the feeder lines 1 and the lines 1 are coupled to their respective valves l. At this time all of the valves are closed. The operator opens valves 5, 5. 5 and Il and the liquid from car I will then illl air trap I2 and car I and the intermediate pipes 1, 5 and II up to the level 52. The operator then closes valve I5, and of course, the liquid in l2 being above level 21 has automatically closed valve 25.

The operator then opens valves I5, 2|, 25 and 25 and starts the motor of pump I1.

The closed air trap I2 will now permit the unloading pump I1 to pull down a considerable vacuum in the top of trap I2; pump I1 creates suction, lowering the liquid level in trap I2 and the suction in combination with the pressure ot the atmosphere entering tank I through valve 5 acts to force the liquid out of tank I in a very much shorter time than would be possible by other means or methods. such as merely draining car I by gravity. Pump I1, being of very high capacity, unloads the cars I in a most rapid manner, but as the cars become unloaded completely, and one car usually becomes unloaded before the others, air will be drawn into the system and this air will cause trouble in Ysystems not employing the present invention.

When one oi' the tank cars becomes empty air will pass through its valve l and down one of feed lines 1 into header 5 and into air trap I2 lowering the liquid level in I2. If this liquid level were allowed to drop enough so that air would be drawn in line I5 this air would get in pump I1 and the-pump would run wild as there would be no load on pump I1 or the motor driving the pump. The result of this might be enough mechanical and electrical overheating of the pump motor to set the loading rack on me. Parts containing explosive mixtures of gasoline might blow up in dangerous fragments, and the re would destroy the tank cars and other equipment depending on whether it was possible to control the nre or not.

In the present invention this filling of pump I1 with air is not permitted, because when the level of liquid in trap I2 falls below line 21 the oat in casing 25, which is floating on liquid supplied through line II, opens valve 25 by means of suitable linkage (not shown). These iloat controlled valves are old in the art and any suitable one o! these old valves may be used.

When valve 25 is open, liquid being pumped by pump I1 is immediately bypassed through recycling bypass 2l and enough liquid pours into trap I2 to keep the end of pipe I5 under liquid at all times, even when all the tank cars I are empty. so that pump I1 will always have sumcient load thereon so that the motor driving pump I1 will not get hot and catch nre, or the pump be inlured by high speed.

The air which finally will enter the header 5 and air trap I2 will finally release the vacuum, and when the tank cars are all nearly empty and the net positive suction head is low, the unloading pump I1 will deliver liquid faster through pipe I5 than the liquid will gravitate into the air trap I2 but gassing up of the pump is prevented by the liquid level iloat control 25 opening valve 25, which is preferably a motor valve. and thus bypassing liquid from the pump discharge pipe I9 to maintain the liquid level at level'21 in the air trap so that the pump I1 always has a proper load. When the tank cars are empty the motor of pump I1 is cut on', all the valves are closed and pipes 1 are disconnected at 5 and 5 and tank cars I removed from siding 2.

Obviously while the method and apparatus of the invention are shown in the important situation where railroad tank cars are unloaded, the source of liquid need not be a railroad tank car I, but may be any source, either of a vehicular or non-vehicular nature, and pipe I9 may discharge to any type receiver. 'I'he type of motor or turbine driving pump I1 is not critical as any type pump and driver may be injured by running wild.

It is believed obvious, therefore, that I have devised a method and apparatus suitable for carrying out the objects of the invention, and that minor changes and modincations may be made by those skilled in the art without departing from the spirit of my invention, the scope of which is deilned by the following claims.

Having described my invention, I claim:

l. An apparatus for unloading a tank car containing a liquid, which comprises an elongated upright air-trap extending from a point at least as high as the level of the top of said tank car to a level well below the bottom of said tank car; a conduit joining the bottom of said tank car and the bottom portion of said air-trap; a discharge conduit leading from the bottom portion of said airtrap; a pump in` said discharge conduit; a by-pass conduit leading from said discharge conduit downstream from said pump to the lower portion of said air-trap at a point below the level of the bottom of said tank car; a valve in said by-pass; a liquid-level responsive means operatively con- 5 nected with said air-trap on a level with the bottom of said tank car; and operative means joining said liquid-level responsive means and said bypass valve to open said by-pass valve when the liquid level in said air-trap falls to said level.

2. In a. system for removing liquid from a liquid supply source the combination which comprises, an elongated upright air-trap extending from a level above the top of said liquid supply source to a level below the bottom of said liquid supply source; a liquid conduit connecting the bottom of said liquid supply source with the bottom portion of said air-trap; a valve for closing the upper end of said air-trap; a liquid discharge conduit leading from the bottom portion of said air-trap; a discharge pump in said discharge conduit; a by-pass line connecting the discharge side of said pump to the lower portion of said airtrap; a liquid level control connected to said airtrap on a level with the bottom of said liquid sup- 20 ply source; and a valve in said by-pass conduit REFERENCES CITED The following references are 'of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,633,483 Graham June 21, 1927 2,061,013 Wade Nov. 1'1, 1936 2,313,269 Sadtler Har. 8, 1943 15 2,354,693 Martin Aug. 1, 1944 FOREIGN `I *A'IEN'IS Number Country Date 102,732 Great Britain Oct. 4, 1917 503,356 France 1hr. 16, 1920 

